Introduction. The paper concentrates on a main building of the Musin-Pushkin estate in Spartakovskaya Street in Moscow, and in some way is a continuation of the previously touched upon topic, covered in the work “Shepelev’s house in the main house of the Musin-Pushkin Estate in Moscow based on historical, architectural and field studies”, published in the journal Vestnik MGSU. 2023. Vol. 18. Issue 6. This paper detailed the history of the first stages of the formation of the main house and revealed its original appearance. However, it would be unfair not to cover the subsequent stages of the existence of the homestead and its main building in particular. In this regard, the need to write this work arose. The purpose of this paper is to examine the original “Baroque” volume revealed by the previous study in the context of later, including valuable, layers, and, as a consequence, to formulate a restoration concept of such a complex multi-component building.

Materials and methods. The comparative-historical method was used as a research method, which allowed us to examine the research materials in a circle of stylistically and typologically similar examples. Examples of restoration work from previous years, applied to similar multi-component buildings with a rich construction history, were also considered. An analysis of the methods of restoration and preservation of more ancient fragments applied to these buildings was conducted.

Results. As a result of the conducted research, the construction periodization of the monument was revealed, the existing volumetric-planning structure was dated, the original elements of the building were discovered and studied, and later stratifications were identified. All this made it possible to propose a restoration project for the main house of the estate with the implementation of architectural revelations of more ancient sections.

Conclusions. The proposed restoration project is the result of comprehensive studies and allows to express the historical appearance of the building with the disclosure of its earlier volumes. Thus, the main house of the estate will enrich the texture and decorate the historical space of one of the most interesting estate ensembles in Moscow.

Introduction. Russia’s sovereignty extends to significant areas of the sea, and a fairly large number of economic activities that are formed in marine areas need spatial planning and legal regulation. The research methodology is based on spatial and regulatory approaches. The paper presents the methodology and structure of the marine integrated plan, proposes a system of interrelated territorial and marine planning documents, and examines the principles of development of coastal territories and coastal waters of the seas as interrelated planning objects. The use of urban planning methods and approaches of territorial planning is proposed to differentiate the marine area by functional use for various subjects of marine activity. Territorial and marine spatial planning unites coastal waters and coastal territories into a single management object. This provision is considered on the example of the coastal regions, for the integrated development of which it is necessary to develop comprehensive marine plans.

Materials and methods. The paper analyzes domestic research and international practice in the field of marine spatial planning, compares the tools of marine and territorial planning, and the implementation options for marine spatial planning tools.

Results. The structure of marine spatial planning documents, the content of marine integrated plans and their relationship to territorial planning documents are substantiated and proposed.

Conclusions. The implementation of marine spatial planning at the national and regional levels will further strengthen the country’s position in the new geopolitical developments in the development of the Arctic, Pacific and Atlantic seas. Marine spatial planning is also of great importance for eliminating cross-sectoral inconsistencies between the subjects of marine activities and authorized control bodies.

Introduction. Suspended buildings with rigid core have a number of important design features, which consist in increased flexibility of their load-bearing elements. This can be used to reduce the seismic load on the structures of high-rise buildings. However, the technical difficulties of construction, as well as calculation methods that did not allow receiving data on the behaviour of suspended structures under seismic impact, served as an obstacle to the use of this system in the construction of high-rise buildings. Another approach to providing seismic protection for high-rise buildings is the installation of dynamic absorbers. Suspended structures in buildings with a rigid core can potentially act as dynamic absorbers. Modern methods of calculating mathematical models allow us to verify this assumption. This paper presents a new design solution for a suspended building with a rigid core, as well as an assessment of the influence of engineering parameters of the suspended part of the building on its seismic resistance.

Materials and methods. Numerical modelling of buildings with the proposed design solution under seismic impact was performed in the LIRA software package in a stepwise nonlinear setting. The effectiveness of the considered structural solution of the building is evaluated on the basis of data on the movements and accelerations of load-bearing structures under seismic impact.

Results. The patterns of the influence of the longitudinal stiffness of elastic links and the mass of the upper suspended block of floors on the displacement and acceleration of load-bearing structures of the building were found. A comparative analysis of deformation state of the structure during seismic action was performed, the optimal parameters of suspended structures were determined, allowing to reduce vibrations of the entire building.

Conclusions. A change in the mass of suspended floors and the rigidity of the connections between the elements of suspended building can lead to a decrease in displacements and accelerations of structures and damping system vibrations. Further research can be devoted to the analytical determination of the optimal parameters of suspended structures that ensure the dispersion of seismic action energy.

Introduction. Wind energy plays a key role in the development of renewable energy sources, especially in remote areas of the Arctic with autonomous power systems. Ensuring the reliability and durability of wind turbine supporting structures in the Arctic zone of the Russian Federation is an important scientific and technical task. Unique climatic conditions including low temperature, strong wind loads, snow and icing considerably complicate the design of such facilities. The purpose of the study is to develop a comprehensive methodology of aeroservoelastic modelling of wind turbines to assess the load-bearing capacity of supporting structures and to optimize the load-bearing structural system of wind turbines.

Materials and methods. A 100 kW wind turbine with a height of 30 is considered as an example. Blade element momentum analysis and aeroservoelastic modelling in the QBlade software are used, and the finite-element software FEA NX is used to calculate the stress-strain state of the supporting structural system. The design wind turbine operation modes with different wind and icing conditions are considered. Modelling covers normal and extreme modes, including analysis of dynamic loads and the influence of resonance effects.

Results. A methodology of aeroservoelastic modelling has been developed, which makes it possible to consider complex operational and climatic effects on the elements of wind turbines. The loads on the wind turbine elements in different operating modes and with rotor icing are determined, their extreme combinations are revealed. Strength and stability analysis of support structures is performed. Structural measures are proposed to increase structural system load-bearing capacity. Recommendations on further optimization of wind turbine design for operation in the Arctic conditions are prepared.

Conclusions. The methodology allows considering the climatic factors of the Arctic to assess the load-bearing capacity of wind turbine support structures. The results obtained can be used in the design of S-class Arctic wind turbines, as well as in the development of methodological recommendations for the calculation of wind turbines, to improve the reliability and efficiency of wind turbine designs used in the Arctic zone of the Russian Federation.

Introduction. The practice of metal structure design shows that the actual performance of nodal joint structures is almost never a “pure” hinge, and there is no “absolutely rigid” connection of elements. In EN 1993-1-8, metal structure assemblies are classified as rigid, nominally hinged and semi-rigid depending on the ratio of the initial rotational stiffness of the assembly to the reduced linear stiffness. The relevance of this study lies in the clarification of the criteria for classifying the bases of off-centre compressed columns as rigid, which will allow the EN 1993-1-8 methodology to be used in domestic design practice.

Materials and methods. The study uses comparative analysis of typical solutions for the bases of off-centre compressed columns and assesses their stiffness according to EN 1993-1-8. An analysis of the influence of the pliability of the bases of off-centre compressed columns of single-storey industrial buildings with a sway frames on the design length of the column and the yield strength reduction factor has been performed.

Results. Classification of steel structure assemblies from the point of view of structural performance is given, in accordance with the domestic practice of steel structure design based on SNiP II-23 (СP 16.13330). Differences in the classification of assemblies depending on their rotational stiffness according to EN 1993-1-8 are presented. The stiffness of bases of typical columns is evaluated and recommendations for changing the criterion of their classification are developed.

Conclusions. The stiffness of typical off-centre loaded column bases was assessed. It was found that more than 50 per cent of typical column bases are semi-rigid, which is unacceptable according to EN 1993-1-8. The stiffness of the column bases is less affected by the thickness of the slab and the strength class of the foundation concrete. The stiffness is 60 % dependent on the steel grade and diameter of the anchor bolts and the height of the column. Based on this, it is recommended to revise the design solutions adopted in the standard solutions or the criteria for classifying the column base type as rigid.

Introduction. The problem of ensuring mechanical safety of buildings and structures under emergency impacts of force and environmental character is associated with the need to assess their robustness. The property of robustness of objects is manifested after the onset of an emergency situation and is closely related to the process of assessing the stability of a structural system to progressive collapse. Currently, there are proposals for robustness assessment in conceptual form and in the form of general analytical expressions that require adaptation to a specific structural system. This paper proposes a methodology and an example of the probabilistic indices of robustness calculation.

Materials and methods. The probabilistic index is calculated on the basis of the classical reliability theory with modification of the formula for the reliability index, which includes the values of random values of bending moments perceived by the section and moments caused by external load. The index is calculated for a failure pattern that does not involve the formation of a cable-stayed mechanism, i.e. the progressive failure is localized by the formation of several plastic hinges, taking into account the operation of the concrete in the limit state. A statistical test method is used to model random variables, considering experimental data on load variation and mechanical characteristics of materials.

Results. An example of two scenarios of accidental impacts on the monolithic frame of a multistory building, preventively designed with consideration of the possibility to taking accidental impacts, is considered. The scattering of ultimate bending moments is simulated, the reliability characteristics of elements, the probabilities of failure-free operation of the system with account of localization of progressive failure are calculated, the probabilistic survivability index for each emergency situation is calculated.

Conclusions. The methodology of quantitative assessment of survivability on the basis of probabilistic index, which includes the possibility of failure-free operation of a part of structural elements of the system and failure of individual elements in the zone of localization of emergency impact, is proposed. The operability of the proposed methodology on specific examples is shown, which will allow to estimate the robustness of both designed and reconstructed structural systems.

Introduction. In modern multi-story buildings constructed from various materials, steel frames are increasingly used, which provide flexibility in planning solutions and reduce construction time. Various types of floors, such as reinforced concrete slabs and precast hollow-core slabs, allow faster installation and increase structural strength, and ensure the transfer of horizontal loads. For optimal design of floors made of precast slabs, especially those supported by the bottom flange of steel beams, it is necessary to use numerical modelling using the finite element method to accurately account for the specific features of the structure and improve its efficiency.

Materials and methods. When forming the finite element model, rod elements for columns and beams, as well as finite shell elements for floor slabs, were used, which allows for accurate modelling of their rigidity and behavior under loads. Several approaches were considered to take into account the specific features of precast concrete slabs: the use of rigid rods and contour triangulation, as well as the creation of hinges with joint expansion to model connections and joint operation of elements. The calculations used numerical parameters of rigidity and fixation, and also took into account the features of support and eccentricities, which increases the accuracy of modelling and allows for the evaluation of forces and deflections in the structure.

Results. The maximum vertical displacements of beams for both considered variants of numerical modelling are determined. Bending moments in beams are obtained and a comparison of the obtained values for numerical and theoretical calculations is performed.

Conclusions. Numerical analysis has shown that modelling precast concrete slabs using contour triangulation (without using rigid rods) more accurately reflects the nature of the operation of the floor structure. The forces in the beams obtained with this modelling method are greater than when using rigid rods in the model.

Introduction. Design of pile foundations on subsidence (loess) soils is one of the most urgent tasks in geotechnics. The widespread use of such soils and their high sensitivity to moistening create risks of significant settlements and deformations of buildings. In this regard, it is important to use modern calculation methods and models that allow more accurate prediction of the behaviour of foundations under different operating conditions.

Materials and methods. Two approaches were used to analyze the bearing capacity of pile foundations: calculations according to the normative documentation and numerical modelling in the PLAXIS 2D software package. Hardening Soil was chosen as the design soil model, which takes into account elastic and plastic properties, as well as the influence of soaking and compaction. The bored piles with a widened heel were modelled, which allows for a more realistic assessment of the interaction between the piles and the soil.

Results. Numerical calculations showed that when soils are soaked, the maximum settlement increases from 6.38 to 14.58 cm, and when taking into account the soil’s own weight — up to 15.21 cm, which is close to the maximum permissible values according to SP22.13330.2016. The use of widened piles made it possible to achieve a more uniform distribution of loads and reduce deformations. In addition, methods for reducing subsidence are considered, including preliminary soaking, soil strengthening and drainage measures.

Conclusions. The simulation results confirmed the effectiveness of the Hardening Soil model for analyzing settlements on subsidence soils. The use of bored piles with a widened heel and engineering measures to strengthen the foundation helps to reduce settlements to standard values, ensuring the reliability and durability of structures. The work emphasizes the importance of an integrated approach to the design of foundations on complex soils.

Introduction. Dynamic pressure is measured in many areas of human activity. It is often not possible to place a sensor directly at the pressure receiver point. Connecting tubes have to be used. This paper discusses the diagnostics of a measuring system for obtaining dynamic flow characteristics in a model of a hydraulic turbine spillway. The purpose of this study is to determine the optimal length of the pressure connecting line and to check the transfer characteristics of the measuring system used.

Materials and methods. A special stand was created for diagnostics of the measuring system. The software for signal processing is implemented in the LabVIEW graphical programming environment. The algorithm for converting sensor signals from the time domain to the frequency domain was the discrete Fourier transform (DFT). The measuring system used pressure sensors XGZP6857A. An analog-to-digital converter (ADC) NI USB 6225 was used. Calibration was performed using the standard method by conducting “reference” experiments in the AeroLab aerodynamic setup. The reference device is the differential digital pressure gauge ECO-INTECH DMC-01M.

Results. As a result of the experiments, pressure pulsation values were obtained for 6 different lengths of connecting tubes. The following lengths of connecting tubes were used in the experiments: 20, 40, 70, 150, 400, 900 mm. Pressure pulsations were recorded in the range from 0 to 70 Hz with a step of 10 Hz. During further analysis of the signals, pressure pulsation spectra and the dependence of the pressure pulsation amplitude on the length of the connecting tube were obtained.

Conclusions. The setup described in the paper can be used for dynamic calibration of pressure sensors in the frequency range up to 70 Hz with different lengths of connecting tubes. The measuring system discussed in the paper can be used to obtain dynamic characteristics of flow in the model of the hydraulic turbine spillway when copper connecting tubes up to 400 mm long are used.

Introduction. Electric water boilers are one of the options for heat generators used in autonomous heat supply systems. Compared to traditional heat generators on hydrocarbon fuel, they are cheaper, easier to operate and install, and safer. In a number of regions of the country, electricity tariffs allow them to compete with traditional boilers in terms of economic indicators. The purpose of the work — to determine and compare the energy efficiency indicators of electric heat generators with different types of heating chambers with water and antifreeze coolants. To assess the possibility of starting the heat supply system from a supercooled state.

Materials and methods. The research is experimental in nature, the tests were conducted on the research stand of the “Arderia” plant. The characteristics of the energy efficiency of electric heat generators with a volumetric heating chamber with heating elements in contact with the coolant and a flow chamber of indirect surface heating were determined. Tests of starting the system in a freezer were conducted.

Results. The energy efficiency coefficients of the studied samples of electric heat generators were determined, amounting to an average of 93.5 % for volumetric heating chambers and 0.97 % for flow-type chambers. The components of heat losses of electric generators were classified. The use of antifreezes reduces the energy efficiency of heat generators by 2.1 %. The possibility of starting a heat supply system with an electric heat generator with a flow-type heating chamber from a supercooled state with a temperature of minus 16 °C was confirmed.

Conclusions. The results of the study showed significant advantages of electric heat generators with a flow-type heating chamber with indirect surface heating over thermal electric generators with a volumetric heating chamber.